A particular problem with known piston rings is that they are not sufficiently resistant to wear. Improved wear resistance has been accomplished through selection of piston ring base materials. In addition, increased wear resistance has been achieved by coating the piston ring base material with a coating material which has improved wear resistance as compared to the base material. Typical coatings including nitrides, carbides, chromium plating, and ceramic plating. However, known processes for applying these coating are expensive and time consuming.
For example, physical vapor deposition (PVD) of a coating material is known in the art. PVD utilizes a vacuum chamber in which the coating material is evaporated. In one method, chromium metal anodes are utilized. The anodes are vaporized and the chromium becomes nitrided with the introduction of a quantity of nitrogen ions. An electrical potential passed through the articles to be coated ensures that the coating material is deposited on the articles. While providing acceptable wear resistance, the process is expensive. The necessary machinery is expensive and complicated to operate. Further, the PVD process can be cumbersome, thus creating a long cycle time. In addition, PVD is unable to provide a layer of coating material that is consistent or sufficient thickness.
For at least these reasons, the inventors have recognized the need for an improved method for creating wear resistant articles that is more economical, has a shorter cycle time and is capable of producing layers of coating materials that are consistent in thickness and as well as being relatively thick.